Embodiments of the present invention relate to a light guide plate.
Currently, liquid crystal displays (LCDs), especially thin-film transistor liquid crystal displays (TFT-LCDs), have been commonly used. Because a liquid crystal layer in a LCD cannot emit light by itself, a light source is required for the LCD so as to realize image display. In a transmissive type LCD, a backlight module is employed to provide a light source of high and uniform brightness.
FIG. 1 is a cross sectional view of a conventional LCD backlight module. As shown in FIG. 1, the backlight module comprises an optical film layer 1, a light guide plate (LGP) 4, lamp tubes 3, lamp covers 5, and a backlight lamp reflecting plate 2. The optical film layer 1 usually comprises optical films such as an upper diffusing sheet, a prism sheet, a lower diffusing sheet and the like, and can be selectively used as required. The lamp tubes 3 and the lamp covers 5 are provided on both sides of the light guide plate 4. The backlight lamp reflecting plate 2 is disposed below the lamp tubes 3 and the light guide plate 4. In this kind of backlight module, the lamp tubes 3 are the light emitting components and emit light into the light guide plate 4, through which the light is in turn directed into liquid crystal panel positioned above the optical film layer 1 for displaying images.
The above mentioned backlight module is of a side light source mode and has at least the following shortcomings: the light guide plate used is generally in a rectangular parallelepiped shape and is relatively heavy, which is inconsistent with the lightness and portability requirement on a LCD; as the lamp cover is needed to improve the light efficiency, the cost of LCD is increased; and the reflecting plate or reflecting film and the like used therein increases not only the cost but also the weight.